Using the latest hotfix, I could not replicate the issue using the steps you describe. Please update your component to the latest build to fix the issue

We failed to open the Database you attach in the previous post. However, using the setting in the code we are able to replicate the issue in our environment. An issue report has been sent to our developer.

In order to solve this issue, we suggest to set the UseValueListForSorting property on the individual column that has WebValueList. For example in the first sample the code used:

grdObj.RootTable.Columns[1].UseValueListForSorting = ValueListSorting.Yes;
grdObj.RootTable.Columns[2].UseValueListForSorting = ValueListSorting.Yes;

Instead of:

grdObj.RootTable.UseValueListForSorting = ValueListSorting.Yes;

OnRowValidate will only trigger after the user leave a row. For your scenario, during OnRowValidate client side event you could check if there is certain value of the cell is prohibited and returning false to abort the operation. Here is the snippet that show how to abort the operation if the ContactTitle cell has the value of Owner1 and set the focus to ContactTitle cell:

function grdObj_OnRowValidate(rowObject)
{
    var grid = ISGetObject("WebGrid1");

    var cellName = wgGetCellByName(rowObject, "ContactTitle");
    if (cellName.cellValue == "Owner1") {
       grid.GetRowByElement(rowObject).GetCell("ContactTitle").ActivateEdit(); 
       return false;    
    }
	
	return true;
}

You could try using the client side event AfterItemSelected for such scenario. Here is the snippet:

function cmb_OnAfterItemSelected(controlId)
{
	var cmb = ISGetObject(controlId);

	var msg = "Selected item \n" + 
	    "Value: " + cmb.Value + "\n" +
	    "Text: " + cmb.Text + "\n" +
	    "Index: " + cmb.SelectedIndex;
	
	alert(msg);
	
	return true;
}

Our common scenario for WebValueList column is using WebCombo edit type. For example, our EditorTypes.aspx page in WebGrid sample which WebValueList in SupplierID and CategoryID column. Please enable filtering by setting the AllowFilter property to true.

We could also use CustomFiltering which already explained in the WebGrid Documentaion under the article "CustomFilter Event". However, using this approach you will need to have the DataText WebValueList as a hidden column.